The present invention provides compounds, pharmaceutical compositions containing one or more of those compounds or their pharmaceutically acceptable salts, which are effective in inhibiting the binding or function of various chemokines, such TECK, to the CCR9 receptor. As antagonists or modulators for the CCR9 receptor, the compounds and compositions have utility in treating inflammatory and immune disorder conditions and diseases.
Chemokines are chemotactic cytokines that are released by a wide variety of cells and attract various types of immune system cells, such as macrophages, T cells, eosinophils, basophils and neutrophils, to sites of inflammation (reviewed in Schall, Cytokine, 3:165-183 (1991), Schall, et al., Curr. Opin. Immunol., 6:865 873 (1994) and Murphy, Rev. Immun., 12:593-633 (1994)). In addition to stimulating chemotaxis, other changes can be selectively induced by chemokines in responsive cells, including changes in cell shape, transient rises in the concentration of intracellular free calcium ions ([Ca2+]), granule exocytosis, integrin up-regulation, formation of bioactive lipids (e.g., leukotrienes) and respiratory burst, associated with leukocyte activation. Thus, the chemokines are early triggers of the inflammatory response, causing inflammatory mediator release, chemotaxis and extravasation to sites of infection or inflammation.
T lymphocyte (T cell) infiltration into the small intestine and colon has been linked to the pathogenesis of Coeliac diseases, food allergies, rheumatoid arthritis, human inflammatory bowel diseases (IBD) which include Crohn's disease and ulcerative colitis. Blocking trafficking of relevant T cell populations to the intestine can lead to an effective approach to treat human IBD. More recently, chemokine receptor 9 (CCR9) has been noted to be expressed on gut-homing T cells in peripheral blood, elevated in patients with small bowel inflammation such as Crohn's disease and celiac disease. The only CCR9 ligand identified to date, TECK (thymus-expressed chemokine) is expressed in the small intestine and the ligand receptor pair is now thought to play a pivotal role in the development of IBD. In particular, this pair mediates the migration of disease causing T cells to the intestine. See for example, Zaballos, et al., J. Immunol., 162(10):5671-5675 (1999); Kunkel, et al., J. Exp. Med. 192(5):761-768 (2000); Papadakis, et al., J. Immunol., 165(9):5069-5076 (2000); Papadakis, et al., Gastroenterology, 121(2):246-254 (2001); Campbell, et al., J. Exp. Med., 195(1):135-141 (2002); Wurbel, et al., Blood, 98(9):2626-2632 (2001); and Uehara, et al., J. Immunol, 168(6):2811-2819 (2002).
The identification of compounds that modulate the function of CCR9 represents an attractive new family of therapeutic agents for the treatment of inflammatory and other conditions and diseases associated with CCR9 activation, such as inflammatory bowel disease.